Washington — If the recent attacks by fellow Republicans on Mitt Romney’s tenure at Bain Capital seem to be hitting a nerve, as Decoder wrote earlier, it may be in part because they expose a growing split within the GOP - over the role of big business.

In fact, according to a detailed survey by the Pew Research Center, this issue represents the single biggest source of division among Republican and Republican-leaning voters.

Pew’s survey of Political Typology, released last May, broke down most Republican voters into two types: “Staunch Conservatives” and “Main Street Republicans.” In general, Staunch Conservatives and Main Street Republicans look pretty similar: They tend to be from the South and Midwest, live in suburbs, are married, own their own homes, attend church, and are predominantly white (though Staunch Conservatives are even more so than Main Streeters). Staunch Conservatives tend to be somewhat older than Main Streeters, and they have slightly higher education levels. They are less likely to be parents and far more likely to say they “agree” with the Tea Party.

When it comes to specific issues, both groups agree on most. Socially, they are strongly opposed to gay marriage and abortion. They are both highly skeptical about government, concerned about the deficit, and in favor of cutting spending.

But there was one major point of difference. When asked whether they agree or disagree with the following statement: “Business corporations make too much profit,” only 13 percent of Staunch Conservatives agreed, whereas 58 percent of Main Streeters agreed. A second, somewhat related point of difference had to do with business and the environment. When asked whether they agreed with the statement: “Environmental laws cost too many jobs and hurt the economy,” 92 percent of Staunch Conservatives agreed, but only 22 percent of Main Streeters agreed.

Pew also identified two other ideological types that also tend to vote Republican, though they are more likely to identify as Independents: “Libertarians,” and a group they call “Disaffecteds.” While Libertarians tend to be opposed to government and in favor of business (and against regulation), Disaffecteds are opposed to government AND big business. They are the least educated of the Republican voting types, and the most “financially stressed,” according to Pew. Significantly, a full 73 percent of Disaffecteds agreed with the statement that corporations make too much profit.

So what does all this mean, in the context of a likely Republican nominee who is strongly identified with big business and corporate profits? Well, the Staunch Conservatives would likely support Romney on this front - as recent defenses from right-wingers such as Rush Limbaugh illustrate. In fact, ironically, the recent attacks on Romney could wind up helping him win over conservative voters who have up until now been skeptical of him for other reasons. On the other hand, the issue has the potential to hurt Romney among Main Streeters and, most of all, among Disaffecteds.

Interestingly, when the Pew survey was taken last May (before the GOP nomination fight had really begun in earnest - and before many candidates had even entered the race), Romney was the top choice of Staunch Conservatives, Main Streeters, and Libertarians. But Disaffecteds showed almost no support for Romney. They were far more likely to say they wanted a candidate like Mike Huckabee or Sarah Palin - two figures whose political appeal runs more toward the GOP populist end of the spectrum. The latest attacks will likely do little to increase Romney’s appeal among this group.